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Re: Use/misuse of RDF:Value

From: Aaron Swartz <aswartz@swartzfam.com>
Date: Fri, 23 Feb 2001 17:12:02 -0600
To: <lagoze@cs.cornell.edu>, <dc-architecture@jiscmail.ac.uk>, <www-rdf-interest@w3.org>
Message-ID: <B6BC4A61.23652%aswartz@swartzfam.com>
lagoze@cs.cornell.edu <lagoze@cs.cornell.edu> wrote:

> 1. My reading of the rdf schema documentation says that Stefan's
> suggestion to use rdfs:label for the expression of a default value is
> very conventional.  As stated in 5.2 of rdf schema, rdfs:label: "This is
> used to provide a human-readable version of a resource name".  The
> examples throughout the document are multi-language labels for
> definition, which seems to have nothing to do with the purpose for which
> Stephan is using it.

I don't follow -- why is this so? It seems that the usage is just fine.

> 3. Of special concern for the dc-architecture folks, I'm still concerned
> that the hanging of that arbitrary information off a intermediate node
> associated attached to a dc property says espresses that the arbitrary
> information is indeed a value of the dc property.

I once again refer you to the argument in:

http://jiscmail.ac.uk/cgi-bin/wa.exe?A2=ind0102&L=dc-architecture&P=27229

> My reading is that Stu is suggesting a violation of
> RDF schema which says that:

First, one cannot be in "violation" of a schema, one merely has something
which it cannot model.

> A property can have at most one range property. It is possible for it to
> have no range, in which case the class of the property value is
> unconstrained. 

Second, this is widely-believed to be a bug and is expected to be soon
changed.

> That is, I can't write a schema that says a dc property can have a range
> that is either a rdfs:literal or an intermediate node.

Third, I believe that leaving the schema unconstrained would have the same
effect since an intermediate node is a resource and the union of resources
and literals covers (to my knowledge) all possible properties in RDF.

> If we can't express this with an rdf schema then we are left with the a
> rather uncomfortable situation for both the dc community and the rdf
> community, both of whom want to see a common use of technologies.

Even if this was an issue, we could simply omit this constraint from the RDF
schema. There is no need for a schema to include all constraints -- even the
schema for RDF Schema itself is missing several constraints which are
unrepresentable!

-- 
[ Aaron Swartz | me@aaronsw.com | http://www.aaronsw.com ]
Received on Friday, 23 February 2001 18:12:14 GMT

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